Stepladder



May 30, 1950 V. J. BUCKNER STEPLADDER Filed March 20, 1946 all INVENTOR. VInaenZ'J fiuc'luzer BY weww Patented May 30, 1950 UNITED STATES PATENT OFFICE (Granted under the act or March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 1 Claim.

The invention described herein if patented, may I be manufactured and used by or for the Govern- -ment of the United States for governmental purposes without the payment to me of any royalty thereon or therefor.

The present invention relates to step ladders and particularly to one of suitable construction .for use in aiding persons to climb into and out of upper berths.

It is a primary object of the invention to provide a ladder of strong and rigid construction,

preferably of tubular metal for imparting great strength with light weight.

A further object of the invention to provide a ladder having folding steps thereon capable of folding into a compact construction enabling easy handling and stowage.

Another object of the invention is to provide permanent rungs in a ladder having foldable steps whereby the ladder frame is made rigid.

A further object of the invention is to provide a ladder wherein the rungs are so arranged as to support excessive loads on the steps.

It is still another object of the invention to provide a locking device for the folding steps of a ladder to hold the same rigidly open independently of the position of the ladder so that on aweaving, vibrating or unstable fioor,as may be encountered on a train or ship at sea, the steps will be lockedopen to provide maximum safety, and a'locking mechanism operative to hold the steps in folded position whereby to provide a compact structure for handling and to prevent noisy rattling when stowed.

For an understanding of these as well as related and inherent objects, reference is made to the step ladder shown in the accompanying drawings which are intended to be illustrative and not limiting.

Figure 1 is a sectional view through the center of the ladder taken on the line of Figure 2.

Figure 2 is a front elevation of the ladder unfolded and in position for use.

Figure 3 is a detail of one of the step plates showing the mounting and the are through which the step may be rotated.

Figure 4. is an enlarged view in side elevation of the hook shaped upper end of a side member.

Figures 5, 6, '7, 8 and 9 are views taken on lines 5-5, SB, 1-4, 88, and 99 of Figure 2, and

Figure 10 is an enlarged front elevation of the foot of the ladder.

With reference to the drawings, the ladder includes two side members ll bound together by a series of vertically spaced horizontal rungs I2,

which are shown as bars of circular cross section,

welded or otherwise rigidly fastened at each end to a side member, binding the same into a single rigid ladder structure. The side members II as shown in Figure 8 are preferably of metal, hollow,

.metal is preferred only because of its greater strength and rigidity coupled with relatively light weight, which are highly desirable characteristics in a ladder subject to much handling and which must be stowed in minimum space and used under conditions requiring great rigidity and safety.

The upper end of each side member preferably terminates in a hook-like bend l3 which is intended to curve over a horizontal bar forming part of an upper berth (not shown) for purposes of safely supporting the upper end of the ladder.

The bottom of each side member rests on a foot pad Id of resilient material such as rubber, plastic or hollow metal to secure the bottom of the ladder against slipping and form a firm grippingsurface with the floor [5.

Pivotally mounted through pins I6 fitted in holes in the side members ll immediately above the fixed rungs l2 and in complementary horizontal bores in each end are folding step plates l'l. These step plates have a hollowed or ground out portion I 8 on the underside in which the rung will snugly fit when the step is rotated into folded position as shown in the dotted line position of Figure 3. The step plate I! is mounted above the fixed rung ['2 with sufiicient clearance to allow the step plate to be easily rotated about the rung to open or closed position but sufficiently close to the rung to bear the weight of a person on the step plate when suflicient to "cause the plate to sag into contact with the fixed rung.

The side members II are provided with complementary rectangular grooves l9 in the forward edge of each side member and sliding rods 20 20 at points so disposed that when the rods are in the extreme upper ends of the grooves the step plates I! will be open or ready for use, as shown in Figures 1, 2 and 3. As noted, the rods 20 fit smoothly in the grooves 19 and within the general overall contour of the side members, or as shown in Figurellii, the rectangular cross isedtion of the sidemembers and sliding'rodsaremomplementary, so that no portion protrudes. It will be evident, however, that any other shape in groove and sliding rod may be used. To retain tion of the groove is desirably terminated at the point 35 where the locking device joins the side member H and the inner portion bends inward, whereby the ladder is smooth from this point downward. In this arrangement the lower end of the sliding rod is bent inward slightly, as shown'in Figure '7, thesdottedilinesthereof indieating the bent slidingrodin raise'd 'position.

Hand grips 36 are attached to the sliding rods :11) Tat a convenient height for grasping the ladder the rods in the grooves a series of clips or braek ets 23 are fixed over the groove-to eaohdenie -iii the side members. I

The sliding rods are shorter' than the length oi the groove sufficient at least to allow'theistep plates to be folded into closed position when the rods are at substantially theF-lower' 'endof the grooves I!) but are of sufiicientlengthtdcboperate with a, locking device 24 horizontally positioned between thedower nds of the side member's. Theioeling device -2-4 inoludes whom-zontally disposed housing whieh=may =be of simitarl y rectangular section as -the side -members and is divided 1 by pl'ate blankets 25 and 1 2 6 boredt-reoei-ve a-ndsuppert thereinliorizontally slidingand locking bGIt-S Z I The outer n'ds 2 8-of the bolts 2''! are of =sm-aller -'bliam'eter -than the iremainder of 'the' bolt adapted -to 'slide acr oss the grooves 19 in the path 'of the'-slidin-g"-rods-"anii are' fitte'd iii-"holes 29 bored inthe 'walls of the s-ide memb'ers defining the grooves 4'9. 1 The eentral portions of thebolts}? l- 'l'iave' per rna-n'e'ntly fixed-dollarsor-"shoulders-t'fi. n' spr ing 'tl n 'surrminds each b'olir and is bean-nee between the "shoulder '30 Y and the bra'xike't 26 i to --'-ur'g"-e the bolt 2 8 into the groove =19 andhdle- 29,- when-the 'sliding rod has" beenraised-abovetlie bolt. Ihe-slid'ing rods are therefore, made' thesa-me length =as 'the -di'stanee "between the-bolt and top Qr =upper end oif the -groove so i that whenthe 2 bolt thus =fuliy 'losedthe sliding rod-is looked 'in- 'tl re open position vvitl'rthe-step plates attached theri'etoheld rigidly open. The housing 244m the inne side of the ladd'er is "of' smaller *seetion 3| "at middle and "has a sl'ot 3-2 "out there'in extending the distance of the depressed "irii'dcile"pcii tion -"dl to receive p-rotniding ea-rs 33 a ttahed -to inner ends 'of the bolts-Q4. "Thiis =by=pulling the bars 13 '-'towards-eai;h "other the bolts 21 are slid inward against thepressurepf the springsand the ends "of the "bolts 2 8 '"afethus withdrawn from the grooves freein'g" thein 'to downward-movement ofthe sliding rods when the steps are to befolizled.

In the position 'shown in Fig."'7,- with the-rods eitend'ingacross the groove t-lie bolt under the spring-pressure willbearagain'st the rod-2b itself and preventnoise or rattling of *the rods and movement of "the-"step "plates atta-ohd thereto while"in"the elosed position. It is-there'fore,-* ap- 'par'ent" that the l'dckifig'devic is operative'in both open and -closedpositions"regardless of thep'ositioi'rofthe ladder.

To prevent open sharp{portions"from-snagging .tfor mounting, and serve also to facilitate movemerit of the sliding rods to open and close the steps.

"clothing -whenthe -'-ladderis*use d,' the" oute'ripor- 13 Having described. my invention and illustrated an 'embodi'rnrit'thereof, what I claim is:

.Aestep ladder having a pair of side members secnred in spaced relationship by a plurality of fixed 'andsubstantially uniformly spaced rungs,

in oombinationwith step plates pivoted at their ends to said side members independently of said rungs," said step plates being pivoted -surnrountingly of said rungs in -a manner whereby i said rungs will serve i to'su-pport loads on said steps when of sufiici'ent magnitude to-=cause a eer-itral downward deflection of said s'tep's, means for =axially rota-ting said steps-on their pivots inunison *fre'm J an open usable position with their planar "surfaces ata predetermined angle with respect to the front and rear planes of said-ladder to-'a foldedstopped position in abutment with -said rungs and -within'- said planesof: the ladder, releasahle-loeking means oarried by saidside members automatically operable to' hol'd said step actuating means inopen and -folde'd I step positions, and nriariuallyoperable means for releasing-said looking-means.

VINGENT JQBUCKNER.

@REFER'ENCES ACILEED Thefioliowing references-are of =re'cor'd inthe "file of thispatent:

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